NEODyS provides information and services for all Near
Earth Asteroids. Each NEA has its own dynamically generated home
page providing information and services, and a search facility puts
the information in easy reach.

Starting from 1 September 2011 NEODyS is sponsored by ESA, which
pays a portion of the operating costs, both for the background orbit
and risk computations and for the database and web interface; the rest
of the work is provided, as before, by the Department of Mathematics,
University of Pisa, and by IASF-INAF (Rome), with the work of staff,
including some retired.

The ESA participation is through a contract with SpaceDyS srl, a
company of Cascina (Pisa, Italy), which is a startup promoted by same
research group which has built and operated NEODyS for the past 19
years.

The University and Research groups will in the near future
continue to share the work and the responsibility, and are in
any case committed to continue for a long period of time to contribute
with research, innovation and certification functions.

NearEarthObjectsDynamicSite

This is the new version NEODyS-2, implementing the new
error model based upon Farnocchia, Chesley, Chambelain
and Tholen (Icarus 2015). The
orbits have all been recomputed by using star catalog debiasing and
an error model with assumed astrometric errors RMS deduced from the
tests of the paper cited above. Risk files have bene recomputed for
all PHAs, scanning for possible impacts for 100 years in the future; as a
result, many objects do not have anymore a risk file, because the
orbit has improved. A few NEAs have a risk file in NEODYS-2, while
they had none in the old versions, but this is in most cases due to
the increase of the final time of the scan from 2080 (which had been
in use previoulsy) to 2118.

The software used for this version of NEODyS is OrbFit version 5.0.5;
the free distribution can be obtained on request, but needs to be
used by users which do understand the new error model. We have not
yet implemented the correlation model for the astrometric errors, see
Baer et al. (Icarus, in press 2011); a compensating increase of the
RMS has been used as a safety margin. We plan to complete this
additional step towards a fully consistent statistical error model
soon (but no fixed date yet).

The NEODyS service is in some circumstances time critical (e.g.,
during special observation campaigns for asteroids at risk of being
lost and/or with Virtual Impactors). At the moment we cannot provide a
duplicate service to guarantee against network failures.

We are doing an effort to provide NEODyS with online help and
captions. However, it is obviously not possible to explain all the
technicalities involved in such a complex information system. The
Tumbling Stone
site had been created precisely to provide more user friendly
information, including an illustrated dictionary of technical terms,
and comments on the most relevant events and discoveries about Near
Earth Asteroids. Unfortunately this site is not currently
maintained.

The same services for other asteroids, including all numbered and
multiopposition orbit objects, can be accessed at
AstDyS.

How does it work?

These important buttons and links are at the top and bottom of every page:

Details known possibilities of Earth-asteroid collision. We
operate the impact risk monitoring system CLOMON2, providing an
estimate of the urgency of the problem based upon the Palermo
Technical scale .

This is the Tools icon (on the right in the top banner). Clicking
repeatedly on it shows the following tools:
Go to nea,
Current date-time,
MJD-calendar conversor
and, finally, color and font-size selectors. When all the
tools are displayed the icon changes to
▼ .
Clicking on
▼
hides the tools and sets the icon again to
▲ .

◲

Expands the main content area, hiding the banners
and menus, to increase the available on-screen surface for data
browsing. The same icon lets you restore the initial layout.

What's new?

The NEODyS information system has recently changed its web
interface. This was necessary to allow upgrade and maintenance of the
web interface, because the previous version used propietary software
which we could not maintain and which used obsolete libraries. The
new interface will gradually diverge, that is acquire new
functionality. We would appreciate receiving comments on the new
interface.

Other features

We are operating the impact monitoring service CLOMON2. The
risk pages have a new format and contain more information, including
the
Palermo Technical scale for each possible impact.

We are providing a link to the animated orbit diagrams
available from JPL (e.g.,
Apophis).

We are providing proper elements, computed by means of
singular averaging, and encounter conditions; a figure shows the
secular evolution of the proper elements (e.g.,
Apophis).

We compute not only the Minimum Orbital Intersection Distance
(MOID), but also all the stationary points of the distance function
between the orbit of the asteroid and the orbit of the Earth; a figure
illustrates the geometry of the distance function; this is informative
especially in the cases with multiple minima (e.g.,
Apophis).

We include the daily ephemeris for each object to the
database. This allows an observer to search for all NEODyS objects
that are visible now, or are in a certain region of sky, in particular
taking into account the galactic disk. See the
Search section to give it a try.

Radar observations now incorporated into our orbital
solutions. For those objects with radar observations, this results in
substantially improved orbits, with far less uncertainty.

We are now using simpler and constant URL's.
This means that you can put a link
to your favorite asteroid
(e.g.,
Apophis)
or to your favorite observatory
(e.g.,
Highland Road Park Observatory)
on your own web pages. You can also use
bookmarks now, the URL for an object does not change.

What's next?

We are working on the problem of assigning formal uncertainties,
based upon the covariance matrix formalism, to all the quantities
presented in the NEODyS home page of an asteroid. E.g., the perihelion
distance, the MOID, the period, etc., should have a stated
uncertainty.